The Experts below are selected from a list of 2412 Experts worldwide ranked by ideXlab platform
Santosh B. Mhaske - One of the best experts on this subject based on the ideXlab platform.
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Pd(II)-Catalyzed Intramolecular Tandem Olefin Amidation/C–H Activation Protocol for the Syntheses of the Protoberberine Class of Natural Products
Organic letters, 2016Co-Authors: Dnyaneshwar N. Garad, Santosh B. MhaskeAbstract:A Pd(II)-catalyzed intramolecular tandem olefin amidation/C–H activation protocol has been developed for the synthesis of an 8-oxoProtoberberine core. It was successfully applied for the syntheses of (±)-8-oxocanadine, (±)-8-oxotetrahydropalmitine, and (±)-8-oxostylopine, which can be easily converted to the respective Protoberberine natural products. The short synthetic route demonstrated would be useful for the synthesis of a large number of natural products and their analogues featuring a Protoberberine scaffold.
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pd ii catalyzed intramolecular tandem olefin amidation c h activation protocol for the syntheses of the Protoberberine class of natural products
Organic Letters, 2016Co-Authors: Dnyaneshwar N. Garad, Santosh B. MhaskeAbstract:A Pd(II)-catalyzed intramolecular tandem olefin amidation/C–H activation protocol has been developed for the synthesis of an 8-oxoProtoberberine core. It was successfully applied for the syntheses of (±)-8-oxocanadine, (±)-8-oxotetrahydropalmitine, and (±)-8-oxostylopine, which can be easily converted to the respective Protoberberine natural products. The short synthetic route demonstrated would be useful for the synthesis of a large number of natural products and their analogues featuring a Protoberberine scaffold.
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Pd(II)-Catalyzed Intramolecular Tandem Olefin Amidation/C–H Activation Protocol for the Syntheses of the Protoberberine Class of Natural Products
2016Co-Authors: Dnyaneshwar N. Garad, Santosh B. MhaskeAbstract:A Pd(II)-catalyzed intramolecular tandem olefin amidation/C–H activation protocol has been developed for the synthesis of an 8-oxoProtoberberine core. It was successfully applied for the syntheses of (±)-8-oxocanadine, (±)-8-oxotetrahydropalmitine, and (±)-8-oxostylopine, which can be easily converted to the respective Protoberberine natural products. The short synthetic route demonstrated would be useful for the synthesis of a large number of natural products and their analogues featuring a Protoberberine scaffold
Dnyaneshwar N. Garad - One of the best experts on this subject based on the ideXlab platform.
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Pd(II)-Catalyzed Intramolecular Tandem Olefin Amidation/C–H Activation Protocol for the Syntheses of the Protoberberine Class of Natural Products
Organic letters, 2016Co-Authors: Dnyaneshwar N. Garad, Santosh B. MhaskeAbstract:A Pd(II)-catalyzed intramolecular tandem olefin amidation/C–H activation protocol has been developed for the synthesis of an 8-oxoProtoberberine core. It was successfully applied for the syntheses of (±)-8-oxocanadine, (±)-8-oxotetrahydropalmitine, and (±)-8-oxostylopine, which can be easily converted to the respective Protoberberine natural products. The short synthetic route demonstrated would be useful for the synthesis of a large number of natural products and their analogues featuring a Protoberberine scaffold.
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pd ii catalyzed intramolecular tandem olefin amidation c h activation protocol for the syntheses of the Protoberberine class of natural products
Organic Letters, 2016Co-Authors: Dnyaneshwar N. Garad, Santosh B. MhaskeAbstract:A Pd(II)-catalyzed intramolecular tandem olefin amidation/C–H activation protocol has been developed for the synthesis of an 8-oxoProtoberberine core. It was successfully applied for the syntheses of (±)-8-oxocanadine, (±)-8-oxotetrahydropalmitine, and (±)-8-oxostylopine, which can be easily converted to the respective Protoberberine natural products. The short synthetic route demonstrated would be useful for the synthesis of a large number of natural products and their analogues featuring a Protoberberine scaffold.
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Pd(II)-Catalyzed Intramolecular Tandem Olefin Amidation/C–H Activation Protocol for the Syntheses of the Protoberberine Class of Natural Products
2016Co-Authors: Dnyaneshwar N. Garad, Santosh B. MhaskeAbstract:A Pd(II)-catalyzed intramolecular tandem olefin amidation/C–H activation protocol has been developed for the synthesis of an 8-oxoProtoberberine core. It was successfully applied for the syntheses of (±)-8-oxocanadine, (±)-8-oxotetrahydropalmitine, and (±)-8-oxostylopine, which can be easily converted to the respective Protoberberine natural products. The short synthetic route demonstrated would be useful for the synthesis of a large number of natural products and their analogues featuring a Protoberberine scaffold
Xinmiao Liang - One of the best experts on this subject based on the ideXlab platform.
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characterization of Protoberberine alkaloids in coptidis rhizoma huanglian by hplc with esi ms ms
IEEE Journal of Solid-state Circuits, 2013Co-Authors: Lingling Ren, Xingya Xue, Xinmiao LiangAbstract:This study aims to qualitatively analyze Protoberberine alkaloids in crude extract of Coptidis Rhizoma using HPLC with ESI-MS/MS. Possible specific molecular weights of Protoberberine alkaloids were firstly deduced according to literatures and were adopted to screen the alkaloids in the HPLC with ESI-MS of crude extract of Coptidis Rhizoma. As a result, 21 Protoberberine alkaloids were found, including compounds of very low concentration and compounds coeluted in one peak. Among these, two compounds were positively identified and verified by comparison with standards. Ten of these compounds were first reported in this study for Coptidis Rhizoma. In addition, chromatographic retention parameters a and c of all compounds were obtained using their retention times under five gradient conditions and were applied to confirm the deduction about the structures of Protoberberine alkaloids by tandem mass data.
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Characterization of Protoberberine alkaloids in Coptidis Rhizoma (Huanglian) by HPLC with ESI-MS/MS.
Journal of separation science, 2013Co-Authors: Lingling Ren, Xingya Xue, Xinmiao LiangAbstract:This study aims to qualitatively analyze Protoberberine alkaloids in crude extract of Coptidis Rhizoma using HPLC with ESI-MS/MS. Possible specific molecular weights of Protoberberine alkaloids were firstly deduced according to literatures and were adopted to screen the alkaloids in the HPLC with ESI-MS of crude extract of Coptidis Rhizoma. As a result, 21 Protoberberine alkaloids were found, including compounds of very low concentration and compounds coeluted in one peak. Among these, two compounds were positively identified and verified by comparison with standards. Ten of these compounds were first reported in this study for Coptidis Rhizoma. In addition, chromatographic retention parameters a and c of all compounds were obtained using their retention times under five gradient conditions and were applied to confirm the deduction about the structures of Protoberberine alkaloids by tandem mass data.
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High performance liquid chromatography-mass spectrometry analysis of Protoberberine alkaloids in medicine herbs.
Journal of separation science, 2007Co-Authors: Lingling Ren, Xingya Xue, Feifang Zhang, Xinmiao LiangAbstract:RP-HPLC is the main method for the analysis of alkaloids. However, peak tailing is a problem that commonly occurs in the separation of alkaloids. In order to overcome this, three kinds of RP columns were compared for the analysis of Protoberberine alkaloids in Coptidis Rhizoma and Phellodendri Cortex in this work. XTerra MS C18 column was the best one which gave the best symmetry factor under the same conditions. With this column, a good separation of the crude extracts of C. Rhizoma and P. Cortex was achieved using 0.1% v/v formic acid buffer and methanol as mobile phase. At the same time, the crude extracts of C. Rhizoma and P. Cortex were analyzed by the LC-ESI-MSn and LC-atmospheric pressure chemical ionization (APCI)-MSn methods. In the analysis of HPLC-ESI/MSn, structures of five Protoberberine alkaloids were elucidated, compared to authentic standards, and data from the literature. At the same time, the structure of a novel compound was elucidated. In the HPLC-APCI/ MSn analysis, there was an interesting phenomenon that the relative abundance of the ions M+ and [M + 2]+ was different for different alkaloids. The possible fragmentation pathways of Protoberberine alkaloids in APCI/MS analysis were studied for the first time in the present work.
Lingling Ren - One of the best experts on this subject based on the ideXlab platform.
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characterization of Protoberberine alkaloids in coptidis rhizoma huanglian by hplc with esi ms ms
IEEE Journal of Solid-state Circuits, 2013Co-Authors: Lingling Ren, Xingya Xue, Xinmiao LiangAbstract:This study aims to qualitatively analyze Protoberberine alkaloids in crude extract of Coptidis Rhizoma using HPLC with ESI-MS/MS. Possible specific molecular weights of Protoberberine alkaloids were firstly deduced according to literatures and were adopted to screen the alkaloids in the HPLC with ESI-MS of crude extract of Coptidis Rhizoma. As a result, 21 Protoberberine alkaloids were found, including compounds of very low concentration and compounds coeluted in one peak. Among these, two compounds were positively identified and verified by comparison with standards. Ten of these compounds were first reported in this study for Coptidis Rhizoma. In addition, chromatographic retention parameters a and c of all compounds were obtained using their retention times under five gradient conditions and were applied to confirm the deduction about the structures of Protoberberine alkaloids by tandem mass data.
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Characterization of Protoberberine alkaloids in Coptidis Rhizoma (Huanglian) by HPLC with ESI-MS/MS.
Journal of separation science, 2013Co-Authors: Lingling Ren, Xingya Xue, Xinmiao LiangAbstract:This study aims to qualitatively analyze Protoberberine alkaloids in crude extract of Coptidis Rhizoma using HPLC with ESI-MS/MS. Possible specific molecular weights of Protoberberine alkaloids were firstly deduced according to literatures and were adopted to screen the alkaloids in the HPLC with ESI-MS of crude extract of Coptidis Rhizoma. As a result, 21 Protoberberine alkaloids were found, including compounds of very low concentration and compounds coeluted in one peak. Among these, two compounds were positively identified and verified by comparison with standards. Ten of these compounds were first reported in this study for Coptidis Rhizoma. In addition, chromatographic retention parameters a and c of all compounds were obtained using their retention times under five gradient conditions and were applied to confirm the deduction about the structures of Protoberberine alkaloids by tandem mass data.
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High performance liquid chromatography-mass spectrometry analysis of Protoberberine alkaloids in medicine herbs.
Journal of separation science, 2007Co-Authors: Lingling Ren, Xingya Xue, Feifang Zhang, Xinmiao LiangAbstract:RP-HPLC is the main method for the analysis of alkaloids. However, peak tailing is a problem that commonly occurs in the separation of alkaloids. In order to overcome this, three kinds of RP columns were compared for the analysis of Protoberberine alkaloids in Coptidis Rhizoma and Phellodendri Cortex in this work. XTerra MS C18 column was the best one which gave the best symmetry factor under the same conditions. With this column, a good separation of the crude extracts of C. Rhizoma and P. Cortex was achieved using 0.1% v/v formic acid buffer and methanol as mobile phase. At the same time, the crude extracts of C. Rhizoma and P. Cortex were analyzed by the LC-ESI-MSn and LC-atmospheric pressure chemical ionization (APCI)-MSn methods. In the analysis of HPLC-ESI/MSn, structures of five Protoberberine alkaloids were elucidated, compared to authentic standards, and data from the literature. At the same time, the structure of a novel compound was elucidated. In the HPLC-APCI/ MSn analysis, there was an interesting phenomenon that the relative abundance of the ions M+ and [M + 2]+ was different for different alkaloids. The possible fragmentation pathways of Protoberberine alkaloids in APCI/MS analysis were studied for the first time in the present work.
Shuying Liu - One of the best experts on this subject based on the ideXlab platform.
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structural analyses of Protoberberine alkaloids in medicine herbs by using esi ft icr ms and hplc esi msn
Journal of Pharmaceutical and Biomedical Analysis, 2005Co-Authors: Fengrui Song, Cunyu Yan, Zhiqiang Liu, Shuying LiuAbstract:Abstract The Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI–FT-ICR-MS) using sustained off-resonance irradiation (SORI)/collision-induced dissociation (CID) method at high mass resolution has been first applied to investigate the characteristic fragment ions of four Protoberberine alkaloids in medicine herbs. The ESI–FT–ICR SORI-CID experiment results demonstrate that the unambiguous elemental composition of fragment ions can be obtained at high mass resolution, then the logical fragmentation pathways of the Protoberberine alkaloids has been proposed. The characteristic fragment ions of CID and MS n of Protoberberine alkaloids have been discussed, which are specific and useful for the identification of some Protoberberine alkaloid compounds. Then, the extracts of four kinds of medicine herbs have been analyzed by HPLC–ESI–MS n . According to these characteristic fragmentation pathways, the retention time ( t R ) of HPLC and mass spectra of product ion, the structures of six kinds of Protoberberine alkaloids have been identified. And, in the present paper, the selected ion monitoring (SIM) method has been used to separate and identify the alkaloid isomers.
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Structural analyses of Protoberberine alkaloids in medicine herbs by using ESI–FT-ICR-MS and HPLC–ESI–MSn
Journal of pharmaceutical and biomedical analysis, 2004Co-Authors: Fengrui Song, Cunyu Yan, Zhiqiang Liu, Shuying LiuAbstract:Abstract The Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI–FT-ICR-MS) using sustained off-resonance irradiation (SORI)/collision-induced dissociation (CID) method at high mass resolution has been first applied to investigate the characteristic fragment ions of four Protoberberine alkaloids in medicine herbs. The ESI–FT–ICR SORI-CID experiment results demonstrate that the unambiguous elemental composition of fragment ions can be obtained at high mass resolution, then the logical fragmentation pathways of the Protoberberine alkaloids has been proposed. The characteristic fragment ions of CID and MS n of Protoberberine alkaloids have been discussed, which are specific and useful for the identification of some Protoberberine alkaloid compounds. Then, the extracts of four kinds of medicine herbs have been analyzed by HPLC–ESI–MS n . According to these characteristic fragmentation pathways, the retention time ( t R ) of HPLC and mass spectra of product ion, the structures of six kinds of Protoberberine alkaloids have been identified. And, in the present paper, the selected ion monitoring (SIM) method has been used to separate and identify the alkaloid isomers.
